The present invention relates to a mechanical pushing, or thrust devices, and in particular to a new and useful pushing mechanism that can be utilized in a variety of fields where precise yet strong pushing force is needed.
A wide variety of mechanical pushing devices are known. Many of these use externally threaded shafts which rotate within internally threaded nuts for axial movement of one of the threaded components. The shaft is driven either directly or indirectly by a motor or other rotary drive mechanism and the shaft is either axially fixed or axially moveable, in addition to its rotary motion.
U.S. Pat. No. 2,247,562 is an example of a thrust mechanism having a moveable threaded shaft. Other U.S. patents which are relevant to the pushing mechanism of the present invention are U.S. Pat. Nos. 2,490,040; 2,818,743; 3,361,240; 3,606,801; 3,727,472; 4,000,661; 4,496,865; and 4,858,491.
U.S. Pat. No. 3,361,240 requires two elements attached to the rotor of a motor rather than a single slotted tube which will be explained later and used in accordance with the invention. U.S. Pat. No. 2,818,743 uses angular motion for an angular function whereas the present invention converts angular motion to linear motion. U.S. Pat. No. 4,000,661 is a moving nut system as are U.S. Pat. Nos. 3,606,801; 4,848,491; 3,727,472 and 2,490,040.
U.S. Pat. No. 2,247,562 uses various parts to achieve axial movement in a complex arrangement.
U.S. Pat. No. 4,496,865 uses an output shaft connected directly to a spindle and a moving nut. The motor appears to move in this arrangement.
A need remains for a simple, yet rugged, pushing mechanism which is both extremely accurate and useable, for example, to move microscope stages, in micro hardness testers and similar small movement, accurate devices, and which is also appropriate for heavy uses such as for compressing hydraulic cylinders for hydraulic applications.